Focusing Performance of Terahertz Zone Plates with Integrated Cross-shape Apertures

Minkevičius, Linas; Madeikis, Karolis; Voisiat, Bogdan; Kašalynas, Irmantas; Venckevičius, Rimvydas; Račiukaitis, Gediminas; Tamošiūnas, V.; Valušis, Gintaras

doi:10.1007/s10762-014-0086-8

Cited by 23 publications

(11 citation statements)

References 4 publications

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“…[ 106 ] It was shown that terahertz zone plates with integrated resonant fi lters are a powerful tool to manipulate the THz laser beam profi le, aiming to fi nd an optimal design to reveal the effect of zone number and the infl uence of the plate thickness. [ 107 ] Further, it was demonstrated that the fl at optics technology can serve as an effective instrument to integrate THz optics and sensing elements in one chip. [ 108 ] The DLW method was applied to produce the zone plate either in 30 µm-thick steel [ 106 ] or in a 200 nm-thick gold layers deposited on one of the bottom surfaces of an InP wafer with integrated InGaAs bow-tie detectors.…”

Section: Thz Plasmonic Responsementioning

confidence: 99%

Recent Advances in Laser Utilization in the Chemical Modification of Graphene Oxide and Its Applications

Trusovas

Račiukaitis

Niaura

et al. 2015

Advanced Optical Materials

155

110

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the manipulation of graphene and its derivatives occupy a relatively insignifi cant part, i.e., less than 1%. The fi rst publications on graphene modifi cation with laser irradiation appeared in 2008, however, since 2010, the number of publications has risen exponentially.Graphene oxide (GO) has emerged as a versatile material for nanocarbon research. Several types of oxygen-containing functional groups present on the basal plane, and the sheet edge allows GO to interact with a broad range of organic and inorganic materials. [ 9 ] Furthermore, GO is an abundant and low-cost material synthesized from graphite or graphite oxide; it retains a layered structure but, at the same time, it can be characterized by the loss of electronic conjugation caused by the oxy groups at the edge or plane defects. GO has a potential use in energy, [ 10 ] electronics, [ 11 ] molecular sensing areas, [ 12 ] catalysis, [ 13 ] etc. Moreover, it can be reduced chemically or thermally in order to achieve graphenelike properties. [ 14 ] The material produced during such a procedure is usually referred to as "reduced GO" (rGO). However, residual defects such as remnant oxygen atoms, [ 15 ] Stone-Wales defects (pentagon-heptagon pairs), [ 16 ] and holes [ 17 ] appearing due to the loss of carbon (in the form of CO or CO 2 ) from the basal plane [ 18 ] limit the electronic quality of rGO.A laser is a powerful tool which is used for various applications in industry, medicine, science, and material processing. [ 19 ] It is usually employed in different processes such as ablation, etching, cutting of various materials, as well as direct A dramatic rise in research interest in laser-induced graphene oxide (GO) reduction and modifi cation requires an overview of the most recent works on this subject. Typical methods for the recognition and confi rmation of modifi ed graphene and its derivatives, such as Raman, Fourier-transform infra-red (FTIR), X-ray photoelectron (XP), and ultraviolet-visible (UV-vis) spectroscopies, are introduced briefl y in this review. A major part of the survey is devoted to the main modifi cation ways and the laser parameters used in the literature. A discussion of possible reduction and modifi cation mechanisms is also presented. Recent applications, especially in the biomedical fi eld such as cell therapy treatment, as well as signifi cant results of GO modifi cation, are discussed in detail. Finally, perspectives for the application of laser-induced GO modifi cations in passive THz photonics and biomedicine are briefl y addressed.

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Section: Thz Plasmonic Responsementioning

confidence: 99%

Recent Advances in Laser Utilization in the Chemical Modification of Graphene Oxide and Its Applications

Trusovas

Račiukaitis

Niaura

et al. 2015

Advanced Optical Materials

155

110

View full text Add to dashboard Cite

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“…To illustrate advantages of combination of the zone plate and laser-ablated resonant filter, images of 0.76 THz laser beam focused with conventional zone plate and the zone plate containing resonant filters were measured using CMOS fieldeffect transistors with nanometric gates as THz sensors with a pixel size of 100x100 11m2. One can also notice that ripples around the central maximum are much weaker for a case of the cross-shaped filters integrated zone plates; diameter of the focused beam spot is smaller, and the focusing performance is higher than that of the conventional zone plate [7].…”

Section: Experiments Al Resul Ts and D1scusstonsmentioning

confidence: 99%

Compact room temperature terahertz imaging: Towards on-chip integration

Valušis

Minkevičius

Kašalynas

et al. 2016

2016 21st International Conference on Microwave, Radar and Wireless Communications (MIKON)

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On-chip integration of secondary diffractive optics and bow-tie-shaped InGaAs-based terahertz detectors is presented. Zone plates were produced directly on the bottom surface of a 500 J.lm-thick semi-insulating InP substrate employing direct laser write technique. Integration of the bow-tie detector and the zone plate allows to enhance detection more than one order of magnitude at 0.76 THz. Good correlation between experimental data and 3D finite-difference time-domain simulation results is found. It is confirmed that observed detection enhancement is caused mainly by the focusing performance of the zone plate.

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“…The group of Gintaras Valušis described manufacturing of lenses by laser patterning of silicon [72], next used for imaging [73], or used laser ablation to integrate FZP on-chip of detector [74]. They also proposed a manufacturing technique using cross-shaped apertures (being a resonant filter) [75][76][77][78] to select the THz frequencies ( Fig. 6) and here, a thin structure with focal length smaller than the lens diameter was designed which unequivocally determined dominance of DOEs over their refractive counterparts in such applications.…”

Section: Fresnel Zone Plates and Diffractive Lensesmentioning

confidence: 99%

Terahertz Diffractive Optics—Smart Control over Radiation

Siemion

2019

J Infrared Milli Terahz Waves

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Over the last 20 years, thin and lightweight optical elements have become very desirable, especially for the terahertz (THz) range. Reduction of the volume of optical elements alongside an increase in their effective efficiency has begun a new direction of research leading to many practical applications. On top of that, diffractive optical elements can not only focus the incident beam, but also can shape the incoming wavefront into a desirable distribution or can redirect the energy. Starting from theoretical calculations of Fourier optics, diffractive elements have been transformed and nowadays form complicated structures that do not resemble a typical Fresnel lens. The precise control over a phase shift introduced by the designed element creates an opportunity to almost freely transform an incident wavefront. Moreover, the vast diversity of computer-generated holograms (also called synthetic) contributes substantially to this topic. Diffractive elements have a great impact on THz optical systems because their manufacturing is very simple in comparison with any other range of radiation (infrared, visible, ultraviolet, etc.). This review paper underlines developments in evolution of diffractive optics and highlights main principles and technological approaches for fabrication of diffraction optics within the terahertz range, thus serving as a guide to design and production considerations.

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Focusing Performance of Terahertz Zone Plates with Integrated Cross-shape Apertures

Cited by 23 publications

References 4 publications

Recent Advances in Laser Utilization in the Chemical Modification of Graphene Oxide and Its Applications

Recent Advances in Laser Utilization in the Chemical Modification of Graphene Oxide and Its Applications

Compact room temperature terahertz imaging: Towards on-chip integration

Terahertz Diffractive Optics—Smart Control over Radiation

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